This application claims the benefit of: Korean Patent Application No. 2000-28396, filed on May 25, 2000; Korean Patent Application No. 2000-28397, filed on May 25, 2000; and Korean Patent Application No. 2000-35105, filed on Jun. 24, 2000 the entirety of each of which is hereby incorporated by reference for all purposes as if fully set forth herein.
1. Field of the Invention
The present invention relates to a display device, and more particularly, to a liquid crystal display (LCD) device and a method for manufacturing the same.
2. Discussion of the Related Art
Ultra-thin sized flat panel displays having a display screen with a thickness of several centimeters or less, and in particular, flat panel LCD devices, are widely used in monitors for notebook computers, spacecraft, and aircraft.
Such LCD devices have low power consumption and are easy to carry. In this respect, the LCD device is receiving much attention as an advanced display device that can substitute for a cathode ray tube (CRT).
An LCD device includes a thin film transistor (TFT) substrate, a color filter substrate, and a liquid crystal layer sealed between the TFT substrate and the color filter substrate. The LCD is a non-light-emitting device that can obtain an image effect based on electro-optical characteristics of the liquid crystal layer.
In other words, a TFT array and pixel electrodes are formed on the TFT substrate, while a black matrix pattern, a color filter layer, and a common electrode are formed on the color filter substrate. The TFT substrate and the color filter substrate are bonded to each other by a sealant such as epoxy resin.
A driving circuit is connected with the TFT substrate using a tape carrier package as a medium. The driving circuit generates various control signals and signal voltages to display images.
The development and application of TFT-LCD industries have been accelerated in accordance with an increase of the dimensions and increase of the resolution of LCD devices. To increase the productivity and ensure the low cost, many efforts have been continued in view of simplified process steps and an improvement of yield.
A method for manufacturing an LCD device according to an example of the related art will be described with reference to the accompanying drawings.
FIGS. 1a to 1f are sectional views illustrating process steps of manufacturing a lower substrate of an LCD device according to an example of the related art, and FIGS. 2a to 2e are sectional views illustrating process steps of an upper substrate of an LCD device according to an example of the related art.
A method for manufacturing a lower substrate of an LCD device will be described with reference to FIGS. 1a to 1f. 
As shown in FIG. 1a, a metal layer which is a material for a gate electrode, such as Al, Ta, Cr, and Al alloy, is formed on a first insulating substrate 1. A gate electrode 2 is formed by a patterning process using a first mask (not shown).
As shown in FIG. 1b, a gate insulating film 3, preferably of SiNx, is formed on the first insulating substrate 1 including the gate electrode 2 by a chemical vapor deposition (CVD) process. A semiconductor layer 4 is then formed on the gate insulating film 3 over the gate electrode 2.
As shown in FIG. 1c, the semiconductor layer 4 is patterned using a second mask (not shown) to form an active pattern 4a. A metal layer 5 such as Al, Cr, Mo, and Al alloy is formed by a sputtering process and then selectively removed to form a source electrode 6a and a drain electrode 6b, as shown in FIG. 1d. The source and drain electrodes 6a and 6b are formed by an etching process using a third mask (not shown). A passivation film 7 is formed on the entire surface, including the source and drain electrodes 6a and 6b. 
As shown in FIG. 1e, a contact hole 8 is formed using a fourth mask (not shown) to expose a portion of the drain electrode 6b. As shown in FIG. 1f, an indium tin oxide (ITO) layer for a pixel electrode is formed on the entire surface so that the layer is electrically connected with the drain electrode 6b through the contact hole 8. The ITO layer is patterned by an etching process using a fifth mask (not shown) to form a pixel electrode 9.
A method for manufacturing an upper substrate for an LCD device will now be described with reference to FIGS. 2a to 2e. 
As shown in FIG. 2a, a light-shielding material is formed on a second insulating substrate la and patterned by photolithography process using a first mask (not shown) to form a black matrix pattern 12. The black matrix pattern 12 is formed on the second insulating substrate la in a matrix arrangement. The black matrix pattern 12 has a double layered structure of CrOx and Cr or a triple layered structure of CrOx, CrNx and Cr.
As shown in FIG. 2b, a first color filter 14a among red (R), green (G), and blue (B) color filters, is formed on the black matrix pattern 12 by a photolithography process using a second mask (not shown).
Subsequently, as shown in FIGS. 2c and 2d, a second color filter 14b and a third color filter 14c are selectively formed in the same manner as the formation of the first color 14a. FIG. 2c is a sectional view showing the second color filter 14b, and FIG. 2d is a sectional view showing the third color filter 14c. Although not shown, separate masks (third and fourth masks) are respectively required when the second color filter 14b and the third color filter 14c are formed.
After, the black matrix pattern 12 and R, G, and B color filters 14a, 14b and 14c are formed on the second insulating substrate 1a, then, as shown in FIG. 2e, an ITO layer is formed on the entire surface by a sputtering process and is patterned using a fifth mask (not shown) to form a common electrode 16.
Once the upper substrate and the lower substrate are manufactured as above, the two substrates are bonded to each other and liquid crystal material is injected between the substrates through a liquid crystal injection hole. Thus, the process for manufacturing an LCD device according to the example of the related art is completed.
However, the process for manufacturing an LCD device according to the example of the related art has several problems.
Since a total of ten masks are required in manufacturing the lower and upper substrates the manufacturing cost increases and the process time increases due to a number of photolithography processes, thereby increasing total turn around time (TAT).
Accordingly, the present invention is directed to an LCD device and a method for manufacturing the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an LCD device and a method for manufacturing the same that reduces the manufacturing cost and TAT, and improves the productivity by minimizing the number of masks required for the process steps.
Another object of the present invention is to provide an LCD device and a method for manufacturing the same in which a color filter layer is formed on a pixel electrode in a state where a TFT is not driven.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an LCD device according to the present invention includes first and second substrates, a TFT formed in a predetermined region on the first substrate, a pixel electrode formed in a pixel region on the first substrate, a color filter layer formed on the pixel electrode, a black matrix pattern formed in a region other than the pixel electrode, and a liquid crystal layer formed between the first and second substrates.
To further achieve these and other advantages and in accordance with the purpose of the present invention, a method for manufacturing an LCD device having a pixel region defined by gate and data lines, includes forming a TFT on a first substrate, forming a black matrix pattern in a region other than the pixel region, forming a pixel electrode in the pixel region, and forming a color filter layer on the pixel electrode. In forming the TFT, when forming source and drain electrodes, an n+ layer between them is removed. When removing the n+ layer, a gate insulating film in a pad region is also removed by an etching process to remove a gate pad.
In another aspect of the present invention, in forming a TFT, a metal layer for the source and drain, an n+ layer for an ohmic contact, and a semiconductor layer of a-Si are patterned, and the patterned metal layer is selectively removed to form source and drain electrodes and at the same time remove an n+ layer between the source and drain electrodes. When removing the n+ layer, a gate insulating film in a pad region may also be removed to expose a gate pad.
Also, when the metal layer is patterned, a connecting pattern which electrically connects the data line with the drain electrode is formed to apply a power source to the pixel electrode.
Consequently, the number of masks required when forming a plurality of patterns on the substrate is minimized to reduce the manufacturing cost, and a color filter material can be electrodeposited by applying a voltage to the data line only in a state such that the TFT is not driven.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.